One QFI at Linton in the late 70s was definitely a pressed man and seemed to resent flying with students. He seemed over-friendly on the ground but resorted to severe name calling and thumping on the arm if the student couldn't get something right at first attempt. He had to think again about his "instructional methods" when two students threatened him with some return violence. A buddy of mine almost came to blows with him in the circuit. After landing he was marched into the flight commander's office and he never flew with him again. The other student eventually got chopped.
I got this instructor on the rebound after a "reshuffle". After two trips with him it was obvious I wouldn't progress with him because I found myself getting frustrated and angry with him in the air. I went to my flight commander and told him I wanted an instructor change. The answer? He said: "Well someone's got to fly with him!"
I just shrugged my shoulders. I got my instructor change.